Cartridge ammunition for rifles is offered in numerous bullet calibers, with casings of various dimensions. Various cartridges can be grouped together into families based on similar case lengths and diameters. Each cartridge is designed and tested for a particular rifle or group of rifles, and will perform best in similar rifles to what it was designed for.
Shooters generally select a rifle on the basis of a cartridge size and price. Cartridges are similar to screwdrivers, in that not every sized screwdriver is applicable to every situation. For example, the cartridge used to humanly take an elephant would be inappropriate for hunting rabbit and vice versa. Therefore, it has been desirable to have multiple rifles in different calibers for use during different hunting seasons. However, the cost of rifles limit the number of shooters to a few who possess a range of rifles capable of firing every cartridge available. As a result, many shooters would like to have a single rifle capable of accepting a multitude of different cartridge sizes that could be used in a variety of situations. As an example, some hunters go on elaborate expeditions to take a specific animal that requires a cartridge in a certain caliber range and take that animal early in the trip. The hunter then may wish to enjoy the rest of the trip hunting a different animal that requires a different caliber than the first. As a result, the typical hunter would have to pack multiple rifles and would be limited to an animal that has a size that corresponds to the guns that were packed and that were in season. As a result, there is a need for one rifle that is configurable to accept a variety of caliber sizes.